Air braking systems are commonly employed in commercial vehicles, particularly in truck-trailer vehicles. These systems use a pressurized air pneumatic line with a coupling connecting the trailer brake system to the truck brake system. This pressurized air pneumatic line is also known as a pneumatic line. As used herein, a pneumatic line will refer to a pressurized fluid pneumatic line, where the fluid may be predominantly air, other gases, or liquids.
FIG. 1 shows a truck 10 with pneumatic line 20 coupled by coupling 22 to pneumatic line 24 of trailer 12 to deliver the contents of pneumatic line 20 to pneumatic line 24 as found in the prior art.
FIG. 2 shows a typical coupling 22 of FIG. 1 of the prior art showing two coupling components 30 and 32 when connecting pneumatic lines 20 and 24 to deliver the contents of pneumatic line 20 to pneumatic line 24. FIG. 3 shows the separated prior art coupling components 30 and 32 of FIG. 2.
Coupling components 30 and 32, of FIGS. 2 and 3, create coupling 22 by being placed together at about a right angle, then twisted to be essentially parallel. A coupling component pair will refer to pairs of components such as coupling components, 30 and 32, which can form a coupling 22 for pneumatic lines. When coupled 22, the truck 10 braking system controls the trailer 12 braking system based upon the pressure in the pneumatic line including 20-22-24.
The standard braking system operates by assuming that low pressure in the coupled pneumatic line 24, means that the brakes should be applied. However, one problem frequently encountered with the prior art system is that when a truck-trailer turns at a sharp angle, there is a tendency for the coupling components 30-32 to be twisted out of the parallel arrangement shown in FIG. 2. When this happens, even when the coupling remains engaged, there is often a loss of pressure in the pneumatic line 24 sufficient to cause the brakes of the trailer 12 to lock. When the trailer brakes lock up, the truck driver must leave the cab, and reassemble the coupling 22 to get the trailer brakes to unlock.
What is needed is a mechanism protecting a pneumatic coupling 22 from being inadvertently twisted, that is easy to use and quick to apply.